Questions in st-line

Select	Question
	The three straight lines $ax+by=c,\,\,bx+cy=a$ and $cx+ay=b$ are collinear, if
	The solution of equations $x+y=10,2x+y=18$ and $4x-3y=26$ will be
	The coordinates of the foot of the perpendicular from the point (2, 3) on the line $y=3x+4$ are given by
	Coordinates of the foot of the perpendicular drawn from (0,0) to the line joining $(a\cos \alpha ,a\sin \alpha )$ and $(a\cos \beta ,a\sin \beta )$ are
	The coordinates of the foot of the perpendicular from $({{x}_{1}},{{y}_{1}})$to the line $ax+by+c=0$ are
	The foot of the coordinates drawn from (2, 4) to the line $x+y=1$ is
	The co-ordinates of the foot of perpendicular from the point (2, 3) on the line $x+y-11=0$are
	The line $2x+3y=12$meets the x-axis at A and y-axis at B. The line through (5, 5) perpendicular to $AB$meets the x- axis , y axis and the $AB$ at C, D and E respectively. If O is the origin of coordinates, then the area of $OCEB$is
	If A and B are two points on the line $3x+4y+15=0$such that $OA=OB=9$units, then the area of the triangle $OAB$ is
	One vertex of the equilateral triangle with centroid at the origin and one side as $x+y-2=0$is